Formulation and evaluation of novel glycyrrhizic acid micelles for transdermal delivery of podophyllotoxin

Abstract

Context: As the first-line agent for genital warts, podophyllotoxin (POD) could induce extensively skin burning, itching, and erythema. Meanwhile, as a common anti-inflammatory agent, glycyrrhizic acid (GA), also has amphipathic and solubilizing properties, indicating that it might be a promising drug carrier.

Objective: The objective of this study is to formulate and characterize the POD-loaded GA micelles preparation and to evaluate its drug release characteristics and anti-inflammatory properties.

Materials and methods: The novel micelles preparation was prepared by ultrasonic dispersion method and characterized using different scanning calorimetries, dynamic light scattering, and transmission electron microscopies. Subsequently, its encapsulation efficiency (EE), drug-loading content (LC), in vitro skin permeation, in vivo drug retention, and distribution of POD were detected. The anti-inflammatory effect of the preparation was reflected by HE staining and immunohistochemistry in the rat skin.

Results: The POD-loaded GA micelles formed spherical shapes (approximately 10 nm) with an EE of 78.53 ± 2.17% and a LC of 7.293 ± 0.42%. Meaningfully, unlike the extensive distribution of the POD tincture throughout the skin tissue, POD released from the POD-loaded GA micelles mainly located in the epidermis and could maintain steady skin retention for 12 h. Moreover, the POD-loaded GA micelles induced less leukocyte infiltration and inflammatory factors (IL-6 and TNF-α) expression when compared with the POD tincture.

Discussion and conclusion: Our results suggested that the POD-loaded GA micelles could achieve a higher POD distribution in the epidermal layer as well as a lighter skin inflammation. This new POD delivery system might be a potential and promising candidate for genital warts and deserved further researches.

• Anti-inflammation
• glycyrrhizic acid
• micelles
• podophyllotoxin
• skin permeation

Acknowledgements

We would like to sincerely thank the entire faculty in the Research Center of Clinical Medicine in Nanfang Hospital, where we performed this study.

Declaration of interest

The authors report no declarations of interest.